1. Field of the Invention
The present invention relates generally to devices for sealably closing vent apertures provided in the walls of various types of fixtures. More particularly, the invention concerns an improved device for use in temporarily sealing vents or overflow drains of the character typically provided in the upper wall portions of fixtures such as wash basins, sinks, bathtubs, and bidets.
2. Discussion of the Invention
In recent years several hydraulic and pneumatic devices have been developed for clearing blockages in drain lines by forcing fluids under pressure through the water outlet drain of the fixture. Such devices may force water or other liquids under pressure through the drain outlet, or they may be of the pneumatic impact or "air hammer" type which forces compressed air or other gases through the drain and into the sewer line.
Prior art cleanout devices of the aforementioned character lose their effectiveness when used with fixtures having a vent or overflow drain apertures. Such apertures are usually provided in the upper portions of the fixture and function to drain water from the fixture into the drain line connected to the drain outlet if the fixture is accidentally over filled. The overflow drain apertures are, of necessity, in communication with the sewer drain line which, in turn, is in communication with the fixture drain, or outlet. When a fluid pressure type cleanout device is used to clear a blockage in the drain line, the overflow apertures must be sealed. Otherwise the fluid forced through the fixture drain under pressure can flow outwardly through the overflow drain apertures before sufficient fluid pressure can be exerted against the blockage to open the line to normal water drainage from the fixture.
In many instances, the overflow apertures provided in a given fixture are in communication with an internal fluid passageway defined between inner and outer, spaced apart walls. The inner wall of the fixture typically defines the water reservoir while the outer wall defined the exterior surfaces of the fixture. Since, with this type of construction, the overflow apertures are accessible only from the inside of the fixture, effective sealing of the apertures can be difficult. For this reason, most types of prior art overflow drain seals involve the use of tapered plugs which can be inserted into the overflow apertures from the interior of the bowl of the fixture. However, such plugs are typically ineffective in sealing the overflow apertures against fluid pressure which is built up interiorly of the walls of the fixture by fluid pressure type cleanout tools. In instances of stubborn blockage of the sewer drain line, the cleanout tool will generate sufficient pressure within the internal passageway of the fixture to blowout the sealing plugs before clearing the blockage in the line. When this occurs the plugs, along with the backed-up fluid, can be ejected with a force that can cause serious personal injury and cause property damage.
One of the most effective prior art devices ever devised for sealing overflow drain apertures is that disclosed in U.S. Pat. No. 5,004,119 issued to the present inventor. This device includes a novel cam-like mechanism for urging a sealing member into sealing engagement with the fixture wall located adjacent the drain opening. The present invention constitutes an improvement of this earlier device in which the cam-like mechanism is replaced by a simpler and more positive threaded pressure imparting mechanism.
The thrust of the present invention is to provide an improved, easier-to-use and less complicated apparatus which can be employed to effectively seal overflow drain apertures provided in a given fixture against even substantial fluid pressures which may be generated against the sealing member of the apparatus by a pressure type sewer line cleanout tool.